Dr. Valerie Flaherman is applying for a Mentored Patient-Oriented Research Career Development Award (K23) to attain the training necessary for scientific independence in the field of newborn preventive interventions. As a specialist both in pediatrics and in preventive medicine. Dr. Flaherman brings a unique perspective to her long-term research goal of improving population health outcomes by developing targeted interventions in the newborn period. This K23 award will allow her to receive the additional training and mentored research experience she needs to attain her research goals and to establish herself as an independent clinical investigator. To provide her with continued mentoring during the K23 award, she has assembled a multidisciplinary team comprised of her sponsor and primary mentor. Dr. Thomas Newman, Professor of Epidemiology and Biostatistics and Pediatrics, who has extensive experience with clinical research among well newborns, and three co-mentors: Dr. Michael Cabana, Division Chief of General Pediatrics who has expertise in preventive trials in the well newborn population; Dr. Charles McCulloch, an expert in longitudinal methods and state-of-the-art biostatistical analysis; and Dr. Kathryn Lee, who has expertise in nursing interventions in the perinatal period. Breastfeeding reduces the incidence of all of the most common infectious diseases of infancy, yet many infants discontinue breastfeeding early. Dr. Flaherman's research will focus on improving the prevalence of breastfeeding. In Aim 1, she will use retrospective medical record data to develop a clinical risk model to identify healthy term newborns at 36 hours who are at increased risk of weight loss S10% birth weight; this risk model will be used to identify a high-risk group of infants who would benefit from an intervention to promote continued breastfeeding. In Aim 2, she will use focus groups to identify physician and nurse provider messages that influenced breastfeeding choices of mothers of infants falling into this high-risk group; these findings will be used to inform an intervention designed to improve breastfeeding outcomes in infants at high risk for breast feeding discontinuation. In Aim 3, she will conduct a small pilot randomized controlled trial (RCT) ofthe intervention, which will assess feasibility and provide preliminary estimates of effect size and variance that can be used to design a larger-scale, adequately powered RCT to rigorously evaluate the effectiveness of the intervention, to be proposed in a subsequent R01 grant application at the end of the K award.